@Article{ 
  AngPalPar10,
  author = { Angiuli, Luciana and Pallara, Diego and Paronetto, Fabio },
  title = { Analytic semigroups generated in $L^1(Ω)$ by second order elliptic operators via duality methods },
  journal = { Semigroup Forum },
  year = { 2010 },
  volume = { 80 },
  pages = { 255-271 },
  URL = { http://cvgmt.sns.it/paper/2424/ },
  note = { cvgmt preprint}
}